1. Field of the Invention
The present invention relates to a clutch operating system for a vehicle. More specifically, the present invention relates to a system having a manual clutch operating unit and an automatic clutch operating unit that includes a motor.
2. Background Information
Manual transmissions are still the main type of transmission used in buses and trucks. With a manual transmission, a gearshift lever near the driver""s seat is linked mechanically to the transmission by such linking mechanisms as a control rod and the like. Consequently, when shifting it is necessary to drive the gear mechanism by operating the shift lever. Thus, when frequent shifting is required, the shifting operation becomes a large burden for the driver.
In order to solve this problem, remote control manual transmission devices have been developed which are provided with a gear changing device on the manual transmission and a transmission ECU for controlling the gear changing device using an electric signal. With this structure, the gear can be changed relatively easy. Since using only a small amount of strength is required to operate the shift lever, the burden on the driver with regards to shifting is reduced.
Furthermore, in order to further reduce the burden on the driver with regards to shifting, there exist automatic transmissions that are provided with a clutch actuator. The clutch actuator automatically engages and disengages the clutch, thus, making it possible to change gears without depressing a clutch pedal.
There are also so-called semiautomatic transmissions that make it possible to switch selectively between the aforementioned automatic shifting and manual shifting.
The aforementioned clutch actuator drives the clutch using a signal from a transmission ECU. The clutch actuator has, for example, a master cylinder, a motion direction converting mechanism, and a motor. The master cylinder is connected to a slave cylinder that is disposed in the vicinity of the release device of the clutch. The motion converting member has a rod, a worm wheel, and a worm gear. The rod abuts against the piston of the master cylinder. The worm wheel is fixed to the other end of the rod and constitutes a crank mechanism. The worm gear meshes with the worm wheel and is fixed to the rotational shaft of the motor. When the motor rotates, the worm gear rotates the worm wheel, causing the rod to move linearly and drive the piston of the master cylinder. As a result, hydraulic pressure is supplied from the master cylinder to the slave cylinder, the slave cylinder drives the release mechanism, and the clutch disengages.
If the motor malfunctions or otherwise is unable to rotate, the cylinder or other hydraulic mechanism that drives the clutch will become inoperable and the clutch will remain in the engaged or disengaged condition, also being unable to operate.
In view of the above, there exists a need for clutch operating system and a hydraulic mechanism that overcomes the above mentioned problems in the prior art. This invention addresses this need in the prior art as well as other needs, which will become apparent to those skilled in the art from this disclosure.
An object of the present invention is to provide a motorized clutch operating system in which it is possible to operate the clutch with a clutch pedal when there is a problem with the motor.
A clutch operating system for operating a clutch of a vehicle in accordance with a first aspect of the present invention is provided with a hydraulic mechanism, an automatic clutch operating unit, and a manual clutch operating unit. The hydraulic mechanism operates the clutch. The automatic clutch operating unit has a motor that drives the hydraulic mechanism in accordance with a prescribed signal input and executes automatic engagement and disengagement of the clutch. The manual clutch operating unit drives the hydraulic mechanism with a clutch pedal device and executes manual engagement and disengagement of the clutch.
With this clutch operating system, the clutch can be operated using either the motor or the clutch pedal device.
A clutch operating system in accordance with a second aspect of the present invention is the clutch operating system of the first aspect, wherein the hydraulic mechanism is provided with a piston, a first hydraulic unit, and a second hydraulic unit. The piston operates the clutch using hydraulic pressure. The first hydraulic unit is driven by the motor and drives the piston. The second hydraulic unit is driven by the clutch pedal device and drives the piston when the motor malfunctions.
With this clutch operating system, the piston can be driven by using the clutch pedal to operate the second hydraulic unit when there is a problem with the motor and the first hydraulic unit cannot be operated.
A hydraulic mechanism for use in a clutch operating system in accordance with a third aspect of the present invention operates a vehicle clutch using a motor during normal operation and makes it possible to operate the clutch using a clutch pedal device when there is a problem with the motor. Further, the hydraulic mechanism is provided with a first cylinder and a second cylinder. The first cylinder is driven by the motor. The second cylinder can be supplied with hydraulic pressure from the first cylinder and the clutch pedal device. The second cylinder is provided with a cylinder tube, a first piston, and a second piston. The first piston is disposed inside the cylinder tube and is driven by hydraulic pressure from the first cylinder. Further, the first piston supplies hydraulic pressure to the clutch. The second piston is disposed inside the cylinder tube, and drives the first piston when hydraulic pressure is supplied from the clutch pedal device. Further, the second piston also supplies hydraulic pressure to the clutch.
With this hydraulic mechanism, when there is a problem with the motor and the first cylinder cannot be operated, operating the clutch pedal device will cause the second cylinder to drive the first piston. Thus the clutch can be operated by means of the clutch pedal even when there is a problem with the motor.
A hydraulic mechanism for use in a clutch operating system in accordance with a fourth aspect of the present invention is the hydraulic mechanism of the third aspect, wherein an oil reservoir is further provided. The cylinder tube has three ports. The first port communicates between the first cylinder and the space between the first piston and the second piston. The second port communicates with the oil reservoir. The third port communicates with the clutch pedal. The second piston has an oil path and a one-way valve. The oil path communicates between the space and the second port. The one-way valve closes the oil path when hydraulic pressure is applied to the space and opens the oil path when hydraulic pressure is applied to the third port from the clutch pedal.
With this hydraulic mechanism, during normal operation, the first piston is driven when oil is supplied from the first piston to the space of the second piston. When this occurs, the one-way valve of the second piston has closed the passage between the space and the second port.
When there is a problem with the motor and the first piston cannot be operated, both the first and second pistons can be operated by operating the clutch pedal device and supplying hydraulic pressure to the third port.
Assume that at a time when there is a problem with the motor and the first cylinder cannot be operated, the first piston is in the clutch disengaged position and there is a space formed between the first piston and the second piston. In such a case, when the clutch pedal is operated, the one-way valve opens and the oil inside the space passes through the oil path of the second piston and returns to the oil reservoir through the second port. Thus the first piston approaches the second piston and, as a result, the first piston and second piston move as a single unit thereafter.
These and other objects, features, aspects and advantages of the present invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses a preferred embodiment of the present invention.